Adhesive block ethylenic copolymers, cosmetic compositions containing them and cosmetic use of these copolymers

ABSTRACT

Linear block ethylenic copolymer, comprising: at least two blocks having different glass transition temperatures (Tg); at least one of these blocks-having a glass transition temperature of less than equal to 20° C.; the said copolymer also having an adhesion or “tack” value of greater than 1N. Cosmetic composition comprising this copolymer. The copolymer improves the styling power and hold of a hair lacquer, increases the adhesion of a nail varnish and improves the hold and adhesion of a makeup composition.

The present invention relates to novel polymers of specific structure ofthe adhesive block ethylenic copolymer type.

The present invention also relates to a composition, especially acosmetic or pharmaceutical composition, in particular a haircomposition, comprising the said polymer of specific structure.

The invention also relates to the cosmetic use of these polymers fortreating the skin, the nails or the hair.

The hairstyling compositions that are currently the most widespread onthe cosmetics market for shaping and/or holding the hairstyle arestyling gels and mousses or sprays.

These compositions contain one or more polymer resins, one of thefunctions of which is to create links between the hairs. These compoundsare also known as fixers and are mixed with various cosmetic additives.

Moreover, vinyl polymers with high glass transition temperatures areknown in cosmetics from document FR-A-2 439 798 and are especiallyincluded in styling compositions.

In the field of styling compositions, although such polymers allowholding of the hairstyle, they have the drawback of being excessivelybrittle, which does not allow good hold of the hairstyle over time.

To overcome this brittle nature, the polymers are generally plasticizedwith plasticizers, but these plasticizers impair the styling propertiesof the polymer.

There is thus a need for a polymer which, when included in acomposition, in particular a cosmetic composition, allows thiscomposition not to have the drawbacks, limitations, defects anddisadvantages of the compositions of the prior art.

Especially, such a polymer must, in a composition for treating the hair,give greater hold while maintaining a natural effect. In a two-coatcomposition for treating the nails, it must allow good adhesion of thefirst coat, and finally, in a composition for treating the skin, it mustallow the makeup to adhere to the skin, while being comfortable andnon-sticky, without making the skin taut.

The aim of the present invention is to provide a polymer that satisfies,inter alia, the needs, criteria and requirements mentioned above andthat solves the problems of the polymers of the prior art.

This aim and others are achieved, in accordance with the presentinvention, by a linear block ethylenic copolymer, comprising:

at least two blocks having different glass transition temperatures (Tg);

at least one of these blocks having a glass transition temperature ofless than or equal to 20° C.;

the said copolymer also having an adhesion or “tack” value of greaterthan 1N.

A subject of the invention is also cosmetic compositions comprising thesaid linear block ethylenic copolymers.

When they are incorporated into cosmetic compositions, the copolymershaving the specific structure according to the invention make itpossible to obtain extremely advantageous properties, which it would notbe possible to obtain with the polymers of the prior art. In general,these polymers have an adhesive nature and they thus lead tocompositions or systems with improved hold and adhesion.

Thus, when the copolymers according to the invention are used incompositions for treating the hair, such as lacquers or shampoos, theygive greater hold, while maintaining a natural effect. In compositionsfor treating the nails, such as nail varnishes, they increase theadhesion of the first coat. In compositions for treating the skin, i.e.in a wide variety of makeup compositions, the copolymers according tothe invention improve the adhesion to the skin, give a comfortablesensation, do not feel sticky and do not make the skin taut.

The invention also relates to a cosmetic process for making up or caringfor maquillage keratin materials, comprising the application to thekeratin materials of a cosmetic composition according to the invention.

The invention thus also relates to the use of the copolymers accordingto the invention to improve the styling power and hold of a hairlacquer, the use of the copolymers to improve the adhesion of a nailvarnish, and lastly the use of the copolymers to improve the hold andadhesion of a makeup composition.

The copolymers of the invention thus provide a solution to the problemsposed by the polymers of the prior art.

The unexpected advantageous properties of the specific copolymers of theinvention, which are fundamentally linear polymers, arise firstly fromthis linear nature and secondly from the specific nature of the blocksof which they are made.

Specifically, the blocks in the copolymers of the invention are definedby particular glass transition temperatures. There was nothing in theprior art to suggest that by using a specifically linear copolymer, andby setting defined Tg conditions for the blocks of which the copolymeris made, it would be possible to obtain, according to the invention, acombination of excellent properties for the copolymer.

Without wishing to be bound by any theory, the advantageous propertiesof the copolymer according to the invention are considered to arise fromthe fact that the specific structure and the specific choice of theblocks of which it is made promote the phase separation between theblocks.

More specifically, the linear copolymers of the present invention aredefined as being ethylenic copolymers. This means that the monomers fromwhich the blocks that make up this copolymer are derived are monomerscontaining a carbon-carbon unsaturated double bond of ethylenic type.

In addition, specifically, the copolymer according to the invention is alinear copolymer. This means that the invention is not intended to covercopolymers having a non-linear structure, for example branched,starburst, grafted or the like. The linear nature of the copolymers ofthe invention is important for giving the compositions containing it theadvantageous properties described above.

Advantageously, the copolymer according to the invention is afilm-forming polymer, i.e. it is capable by itself, or in the presenceof an auxiliary film-forming agent, at a temperature ranging from 20° C.to 30° C., of forming a continuous (to the naked eye) film that adheresto a keratin support.

According to the invention, the copolymer comprises at least two blocksthat have different glass transition temperatures (Tg), and also atleast one of these blocks of the copolymer has a glass transitiontemperature of less than or equal to 20° C.

Since the glass transition temperature Tg is an essential parameter fordefining the blocks in the copolymer of the invention and, consequently,the copolymer of the invention, it is important to point out that theglass transition temperatures of the blocks in the copolymers used inthe present invention are measured by differential scanning calorimetryfor the dry polymer, at a heating rate of 10° C./minute.

The copolymers according to the invention are also defined by a specificmechanical criterion, which is the “adhesion” or “tack”. According tothe invention, the copolymers have an adhesion or tack that is generallygreater than 1N, preferably greater than 2N and more preferably greaterthan 3N.

This “adhesion” or “tack”, defined by Fmax, is measured by the followingtest.

Fmax is the maximum tensile force, measured using an extensometer,required to detach the respective surfaces, with an area of 0.95 cm², oftwo rigid, inert, non-absorbent glass supports (A) and (B) placed faceto face. The said surfaces were precoated with a composition comprisingthe copolymer to be tested, according to the invention, this coatingcomposition has a solids concentration (C) of 10% (in grams per 100grams of composition), and the surfaces of the supports are coated at arate of 4/C mg/cm².

The surfaces are then dried for 48 hours at 22° C., under a relativehumidity of 50%, and are then subjected for 20 seconds to a compressionof 3 newtons and finally subjected for 60 seconds to traction, at aspeed of 10 mm/minute.

Each block in the copolymer according to the invention is derived fromone type of monomer or from several different types of monomer.

This means that each block may consist of a homopolymer or a copolymer;this copolymer of which the block is made may in turn be random oralternating.

According to the invention, the copolymer comprises at least two blocks,having different glass transition temperatures (Tg). Advantageously, thedifference in glass transition temperatures between these two blocks,having different glass transition temperatures, is generally from 40 to120° C., preferably from 40 to 110° C. and more preferably from 40° C.to 100° C.

The number-average mass of the copolymer is generally from 10,000 to500,000 and preferably from 50,000 to 200,000.

Advantageously, the proportion of the block with a Tg of less than orequal to 20° C. is from 99% to 40% of the polymer, preferably from 95%to 55% and more preferably from 90% to 50%.

Advantageously, the block with a Tg of less than or equal to 20° C. hasa temperature Tg from 20 to −100° C., preferably from 20 to −95° C. andmore preferably from 20 to −90° C.

The block whose glass transition temperature is less than or equal to20° C., which is a homopolymer or a copolymer, is preferably totally orpartly derived from one or more monomers, which are such that thehomopolymers prepared from these monomers have glass transitiontemperatures of less than or equal to 20 ° C.

More preferably, the block whose glass transition temperature is lessthan or equal to 20° C. is a homopolymer consisting of a single type ofmonomer (the Tg of the corresponding homopolymer of which is less than20° C.).

The monomers whose homopolymers have glass transition temperatures ofless than or equal to 20° C. and from which is(are) preferably derivedthe block(s) of Tg≦20° C. of the copolymer of the invention arepreferably chosen from the following monomers:

ethylenic hydrocarbons of 2 to 10 C, such as ethylene, isoprene andbutadiene;

acrylates of formula CH₂═CHCOOR₁, R₁ representing a linear or branched 1to 12 C alkyl group with the exception of a tert-butyl group, in whichone or more hetero atoms chosen from O, N and S is(are) optionallyinserted, the said alkyl group also possibly being optionallysubstituted with one or more substituents chosen from hydroxyl groupsand halogen atoms (Cl, Br, I and F);

examples of groups R₁ are methyl, ethyl, propyl, butyl, isobutyl, hexyl,ethylhexyl, octyl, lauryl, isooctyl, isodecyl, hydroxyethyl,hydroxypropyl, methoxyethyl, ethoxyethyl and methoxypropyl groups,

another example of R₁ for the acrylates are POE (polyoxyethylene)—C₁ toC₁₂ alkyl groups, with repetition of the oxyethylene unit from 5 to 30times, for example methoxy POE, i.e. the groups R₁═R″—(OC₂H₄)_(n)—, withR″═C₁-C₁₂ alkyl and n=5 to 30,

R₁ may also denote a polyoxyethylene group comprising from 5 to 30ethylene oxide units;

the methacrylates of formula:

R₂ representing a linear or branched 3 to 12 C alkyl group, in which oneor more hetero atoms chosen from O, N and S is(are) optionally inserted,the said alkyl group possibly also being optionally substituted with oneor more substituents chosen from hydroxyl groups and halogen atoms (Cl,Br, I and F); examples of groups R₂ are hexyl, ethylhexyl, octyl,lauryl, isooctyl, isodecyl, dodecyl, methoxyethyl, methoxypropyl,ethoxyethyl, POE (polyoxyethylene with repetition of the oxyethyleneunit from 5 to 30 times) and (C₁ to C₃₀) alkyl—POE (with repetition ofthe oxyethylene unit from 5 to 30 times);

the vinyl esters of formula:R₃—CO—O—CH═CH₂

in which R₃ represents a linear or branched 2 to 12 C alkyl group;

examples of such vinyl esters are: vinyl propionate, vinyl butyrate,vinyl ethylhexanoate, vinyl neononanoate and vinyl neodecanoate;

vinyl ethers of a 1 to 12 C alkyl, such as methyl vinyl ether and ethylvinyl ether;

N-(1 to 12 C)alkyl acrylamides, such as N-octylacrylamide.

The monomers that are particularly preferred are: n-butyl acrylate,ethylhexyl acrylate, isobutyl acrylate, methoxyethyl acrylate,ethoxyethyl (meth)-acrylate and n-hexyl (meth)acrylate.

The block with a glass transition temperature of less than or equal to20° C. can, besides the monomers indicated above, and the glasstransition temperature Tg of the corresponding homopolymer of which isless than or equal to 20° C., comprise one or more other differentmonomers known as additional monomers.

This or these additional monomer(s) is(are) obviously chosen such thatthe Tg of the block is less than or equal to 20° C.

Thus, a block of adequate Tg, less than or equal to 20° C., may beformed from a copolymer consisting of a first monomer for which the Tgof the corresponding homopolymer is in the range from more than 20° C.to 200° C. and preferably from more than 20° C. to 120° C., and of asecond monomer for which the Tg of the corresponding homopolymer is inthe range from 20° C. to −100° C.

For example, it will be possible to combine in the copolymer forming theblock a monomer with a Tg (of the corresponding homopolymer) equal to100° C., in a proportion of 35% by weight relative to the total weightof monomers, and a monomer with a Tg equal to −70° C., in a proportionof 65% by weight, and the resulting block will have a Tg of −30° C.

These additional monomers which thus have a Tg for the equivalenthomopolymer of greater than 20° C. are chosen especially from acrylates,methacrylates, meth(acrylamide), vinyl and allylic compounds, etc.

The additional monomers (with a Tg for the correspondinghomopolymer >20° C.) are preferably chosen from the following monomers:

the vinyl compounds of formula:CH₂═CH—R₄,

in which R₄ is a hydroxyl group; a group

a C₃ to C₈ cycloalkyl group; a C₆ to C₂₀ aryl group; a C₇ to C₃₀ aralkylgroup (C₁ to C₄ alkyl); a 4- to 12-membered heterocyclic groupcontaining one or more hetero atoms chosen from O, N and S; aheterocyclylalkyl group (C₁ to C₄ alkyl) such as a furfuryl group; thesaid cycloalkyl, aryl, aralkyl, heterocyclic or heterocyclylalkyl groupspossibly being optionally substituted with one or more substituentschosen from hydroxyl groups, halogen atoms and linear or branched 1 to 4C alkyl groups in which is(are) optionally inserted one or more heteroatoms chosen from O, N, S and P, and the said alkyl groups also possiblybeing optionally substituted with one or more substituents chosen fromhydroxyl groups and halogen atoms (Cl, Br, I and F).

Examples of vinyl monomers are vinylcyclohexane, styrene and vinylacetate.

The acrylates of formula:CH₂═CH—COOR₅

in which R₅ is a tert-butyl group; a C₃ to C₈ cycloalkyl group; a C₆ toC₂₀ aryl group; a C₇ to C₃₀ aralkyl group (C₁ to C₄ alkyl); a 4- to12-membered heterocyclic group containing one or more hetero atomschosen from O, N and S; a heterocyclylalkyl group (C₁ to C₄ alkyl), suchas a furfuryl group; the said cycloalkyl, aryl, aralkyl, heterocyclic orhetero-cyclylalkyl groups possibly being optionally substituted with oneor more substituents chosen from hydroxyl groups, halogen atoms andlinear or branched 1 to 4 C alkyl groups in which is(are) optionallyinserted one or more hetero atoms chosen from O, N, S and P, the saidalkyl groups also possibly being optionally substituted with one or moresubstituents chosen from hydroxyl groups and halogen atoms (Cl, Br, Iand F).

Examples of acrylate monomers are t-butylcyclohexyl acrylate, tert-butylacrylate, t-butylbenzyl acrylate, furfuryl acrylate and isobornylacrylate;

the methacrylates of formula:CH₂═C(CH₃)—COOR₆

in which R₆ is a linear or branched 1 to 4 C alkyl group, such as amethyl, ethyl, propyl or isobutyl group, the said alkyl group alsopossibly being optionally substituted with one or more substituentschosen from hydroxyl groups and halogen atoms (Cl, Br, I and F); a C₃ toC₈ cycloalkyl group; a C₆ to C₂₀ aryl group; a C₇ to C₃₀ aralkyl group(C₁ to C₄ alkyl group); a 4- to 12-membered heterocyclic groupcontaining one or more hetero atoms chosen from O, N and S; aheterocyclylalkyl group (1 to 4 C alkyl), such as a furfuryl group; thesaid cycloalkyl, aryl, aralkyl or heterocyclic or heterocyclylalkylgroups possibly being optionally substituted with one or moresubstituents chosen from hydroxyl groups, halogen atoms and linear orbranched 1 to 4 C alkyl groups in which is(are) optionally inserted oneor more hetero atoms chosen from O, N, S and P, the said alkyl groupsalso possibly being optionally substituted with one or more substituentschosen from hydroxyl groups and halogen atoms (Cl, Br, I and F).

Examples of methacrylate monomers are methyl methacrylate, ethylmethacrylate, n-butyl methacrylate, isobutyl methacrylate,t-butylcyclohexyl methacrylate, t-butylbenzyl methacrylate, methoxyethylmethacrylate, methoxypropyl methacrylate and isobornyl methacrylate;

the (meth)acrylamides of formula:

in which R₇ and R₈, which may be identical or different, each representa hydrogen atom or a linear or branched alkyl group of 1 to 12 carbonatoms, such as an n-butyl, t-butyl, isopropyl, isohexyl, isooctyl orisononyl group, and R′ denotes H or methyl.

Examples of (meth)acrylamide monomers are N-butylacrylamide,N-t-butylacrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide andN,N-dibutylacrylamide. The monomers that are preferred among all thosementioned above are chosen from furfuryl acrylate, isobornyl acrylate,tert-butyl acrylate, tert-butylcyclohexyl acrylate, tert-butylbenzylacrylate, methyl methacrylate, n-butyl methacrylate, ethyl methacrylate,isobutyl methacrylate, styrene, vinyl acetate and vinylcyclohexane.

Examples of these additional monomers that are particularly preferredare methyl methacrylate, styrene, (meth)acrylic acid, isobornyl acrylateand furfuryl acrylate.

This or these additional monomer(s) is(are) generally present in anamount of less than or equal to 50% by weight, preferably less than orequal to 45% by weight and more preferably less than or equal to 40% byweight relative to the total weight of the block with a Tg of less thanor equal to 20° C.

Advantageously, the copolymer according to the invention comprises atleast one hydrophilic block which comprises hydrophilic monomers.

The hydrophilic block may be defined as being a water-soluble orwater-dispersible block.

The polymer forming the block is water-soluble if it is soluble in waterto a proportion of at least 5% by weight, at 25° C.

The polymer forming the block is water-dispersible if it forms, at aconcentration of 5% and at 25° C., a stable suspension of fine,generally spherical particles. The mean size of the particlesconstituting the said dispersion is less than 1 μm and more generallyranges between 5 and 400 nm and preferably from 10 to 250 nm. Theseparticle sizes are measured by light scattering.

The hydrophilic block is preferably a block whose glass transitiontemperature is greater than 20° C. but it may also be a block whoseglass transition temperature is less than or equal to 20° C.

It is known that the hydrophilic monomers whose homopolymers have aglass transition temperature of less than 20° C. are not common.

Accordingly, when the hydrophilic block is a block with a Tg of lessthan or equal to 20° C., it is advantageously a copolymer.

This hydrophilic block then advantageously comprises one or morehydrophilic monomer(s) whose corresponding homopolymers have glasstransition temperatures of greater than 20° C. and one or more othernon-hydrophilic monomer(s) chosen especially from those whosehomopolymers have Tg values of less than or equal to 20° C.

The proportion of the various hydrophilic and non-hydrophilic monomersis preferably chosen such that the whole block consisting of a copolymerhas a Tg of greater than 20° C.

When the hydrophilic block has a glass transition temperature of greaterthan 20° C., it generally comprises from 70% to 100% and preferably from80% to 100% of hydrophilic monomers for which the Tg values of thecorresponding homopolymers are greater than 20° C.

When the hydrophilic block has a glass transition temperature of lessthan or equal to 20° C., it generally comprises from 10% to less than70% and preferably from 20% to 65% of hydrophilic monomers for which theTg values of the corresponding homopolymers are greater than 20° C.

Examples of hydrophilic monomers for which the Tg of the correspondinghomopolymer is greater than 20° C. include cationic monomers, anionicmonomers and nonionic monomers.

Examples of cationic monomers are:

2-vinylpyridine;

4-vinylpyridine;

dimethylaminoethyl methacrylate (DMAEMA);

diethylaminoethyl methacrylate (DEAEMA);

dimethylaminopropylacrylamide; and

the salts thereof, whether they are salts of mineral acids, such assulphuric acid or hydrochloric acid, or salts of organic acids.

These organic acids may comprise one or more carboxylic, sulphonic orphosphonic groups. They may be linear, branched or cyclic aliphaticacids or alternatively aromatic acids. These acids may also comprise oneor more hetero atoms chosen from O and N, for example in the form ofhydroxyl groups.

An example of an acid containing an alkyl group is acetic acid CH₃COOH.

An example of a polyacid is terephthalic acid.

Examples of hydroxy acids are citric acid and tartaric acid.

Examples of anionic monomers are:

acrylic acid, methacrylic acid, crotonic acid, maleic anhydride,itaconic acid, fumaric acid and maleic acid;

styrenesulphonic acid, acrylamidopropane-sulphonic acid, vinylbenzoicacid, vinylphosphonic acid and the salts thereof.

The neutralizer may be a mineral base, such as LiOH, NaOH, KOH, Ca(OH)₂or NH₄OH, or an organic base, for example a primary, secondary ortertiary amine, such as a primary alkylamine, for instance2-amino-2-methylpropanol, or a secondary or tertiary alkyl-amine.

Examples of nonionic monomers are:

hydroxyalkyl (meth)acrylates in which the alkyl group contains from 2 to4 C atoms, in particular hydroxyethyl (meth)acrylate,

vinyllactams, (meth)acrylamides and N—(C₁-C₄)-alkyl(meth)acrylamides,for instance isobutylacrylamide; and polysaccharide (meth)acrylates, forinstance sucrose acrylate.

It should be noted that even though the copolymer comprises ahydrophilic block, the overall copolymer is not necessarily hydrophilic.

The linear block ethylenic copolymers according to the invention arechosen from:

diblock copolymers;

triblock copolymers;

multiblock copolymers containing more than three blocks.

In the case of multiblock copolymers, in which one or two blocks satisfythe criterion of a Tg of less than or equal to 20° C. The other blocksthen have a Tg of greater than 20° C. and less than 200° C.

For example, the copolymers may comprise two blocks having a Tg≦20° C.and one or two blocks having a Tg>20° C.

The copolymers according to the invention may be prepared by anionicpolymerization.

Preferably, however, the copolymers according to the invention areobtained, in a first mode, by controlled free-radical polymerization,but they may also be obtained, according to a second mode, by standardfree-radical polymerization.

First Mode:

The block copolymers according to the invention are preferably obtainedby controlled free-radical polymerization, described especially in “NewMethod of Polymer Synthesis”, Blackie Academic & Professional, London,1995, Volume 2, page 1.

Controlled free-radical polymerization makes it possible to reduce thedeactivation reactions of the growing free-radical species, inparticular the termination step, these being reactions which, instandard free-radical polymerization, irreversibly and uncontrollablystop the growth of the polymer chain.

In order to reduce the probability of termination reactions, it has beenproposed to temporarily and reversibly block the growing free-radicalspecies, by forming “dormant” active species in the form of a bond witha low dissociation energy.

Thus, the polymerization may be carried out according to the atomtransfer technique, or by reaction with a nitroxide, or alternativelyaccording to the “reversible addition-fragmentation chain-transfer”technique.

The atom-transfer free-radical polymerization technique, also known bythe abbreviation ATRP, consists in blocking the growing free-radicalspecies in the form of a bond of C-halide type (in the presence of ametal/ligand complex). This type of polymerization is reflected bycontrol of the mass of the polymers formed and by a low polydispersityindex.

In general, the atom-transfer free-radical polymerization is performedby polymerizing one or more polymerizable monomers via a free-radicalroute, in the presence of:

an initiator containing at least one transferable halogen atom;

a compound comprising a transition metal capable of participating in areduction step with the initiator and a “dormant” polymer chain; and

a ligand that may be chosen from compounds comprising a nitrogen (N),oxygen (O), phosphorus (P) or sulphur (S) atom, which may be coordinatedby a σ bond to the said compound comprising a transition metal, theformation of direct bonds between the said compound comprising atransition metal and the polymer in formation being avoided.

The halogen atom is preferably a chlorine or bromine atom.

This process is described in particular in patent application WO97/18247 and in the article by Matyjasezwski et al., published in JACS,117, page 5614 (1995).

The technique of free-radical polymerization by reaction with anitroxide consists in blocking the growing free-radical species in theform of a bond of C—ONR₁R₂ type, R₁ and R₂ possibly being, independentlyof each other, an alkyl radical containing from 2 to 30 carbon atoms, ortogether forming, with the nitrogen atom, a ring containing from 4 to 20carbon atoms, such as, for example, a 2,2,6,6-tetramethylpiperidyl ring.This polymerization technique is especially described in the articles“Synthesis of nitroxy-functionalized polybutadiene by anionicpolymerization using a nitroxy-functionalized terminator” published inMacromolecules 1997, Volume 30, pages 4238-4242, and “Macromolecularengineering via living free radical polymerizations” published inMacromol. Chem. Phys. 1998, Vol. 199, pages 923-935, or in patentapplication WO-A-99/03894.

The technique of RAFT (reversible addition-fragmentation chain-transfer)polymerization consists in blocking the growing free-radical species inthe form of a bond of C—S type. Dithio compounds such as thiobenzoates,dithiocarbamates or xanthan disulphides are used to do this. Thistechnique is described especially in patent application WO-A-98/58974and in the article “A more versatile route to block copolymers and otherpolymers of complex architecture by living radical polymerization: theRAFT profess”, published in Macromolecules, 1999, Volume 32, pages2071-2074.

Second Mode:

The block polymers according to the invention may also be obtained byusing the standard free-radical polymerization technique by casting themonomers sequentially. In this case, only control of the nature of theblocks is possible (no control of the masses).

This involves polymerizing, in a first stage, a monomer M1 in apolymerization reactor and monitoring, by kinetics, its consumption overtime and then, when M1 is about 95% consumed, introducing a new monomerM2 into the polymerization reactor.

A polymer of block structure of M1-M2 type is thus readily obtained.

The invention also relates to cosmetic or pharmaceutical compositionscomprising the copolymer of specific structure as described above.

Generally, these compositions contain from 0.1% to 60% by weight,preferably from 0.5% to 50% by weight and more preferably from 1% to 40%by weight of the copolymer according to the invention.

These cosmetic compositions according to the invention comprise, besidesthe said polymers, a physiologically acceptable medium, i.e. a mediumthat is compatible with keratin materials, for instance the skin, thehair, the eyelashes, the eyebrows and the nails.

In general, it should be considered that the whole composition isphysiologically acceptable.

The said physiologically acceptable medium generally comprises aphysiologically acceptable suitable solvent, in which the copolymeraccording to the invention is in dissolved or dispersed form.

The composition may thus comprise, as solvent forming a hydrophilicphase, water or a mixture of water and of hydrophilic organicsolvent(s), for instance alcohols and especially linear or branchedlower monoalcohols containing from 2 to 5 carbon atoms, for instance,ethanol, isopropanol or n-propanol, and polyols, for instance glycerol,diglycerol, propylene glycol, sorbitol, pentylene glycol andpolyethylene glycols. The hydrophilic phase may also contain hydrophilicC₂ ethers and C₂-C₄ aldehydes.

Water or a mixture of water and of hydrophilic organic solvents may bepresent in the composition according to the invention in an amountranging from 0% to 99% (especially 0.1 to 99%) by weight, and preferablyfrom 10% to 80% by weight, relative to the total weight of thecomposition.

The composition may also comprise a fatty phase consisting especially offatty substances that are liquid at room temperature (in general 25° C.)and/or fatty substances that are solid at room temperature, such aswaxes, pasty fatty substances and gums, and mixtures thereof. Thesefatty substances may be of animal, plant, mineral or synthetic origin.This fatty phase may also contain lipophilic organic solvents.

As fatty substances that are liquid at room temperature, often known asoils, which may be, used in the invention, mention may be made of:hydrocarbon-based oils of animal origin such as perhydrosqualene,hydrocarbon-based plant oils such as liquid triglycerides of fatty acidscontaining from 4 to 10 carbon atoms, for instance heptanoic or octanoicacid triglyceride, or alternatively sunflower oil, corn oil, soybeanoil, grape seed oil, sesame seed oil, apricot oil, macadamia oil, castoroil, avocado oil, caprylic/capric acid triglycerides, jojoba oil andkarite butter; linear or branched hydrocarbons of mineral or syntheticorigin such as liquid paraffins and derivatives thereof, petroleumjelly, polydecenes and hydrogenated polyisobutene such as parleam;synthetic esters and synthetic ethers, especially of fatty acids, suchas, for example, purcellin oil, isopropyl myristate, 2-ethylhexylpalmitate, 2-octyldodecyl stearate, 2-octyldodecyl erucate andisostearyl isostearate; hydroxylated esters, for instance isostearyllactate, octyl hydroxystearate, octyldodecyl hydroxystearate,diisostearyl malate, triisocetyl citrate, and fatty alkyl heptanoates,octanoates and decanoates; polyol esters, for instance propylene glycoldioctanoate, neopentyl glycol diheptanoate or diethylene glycoldiisononanoate; and pentaerythritol esters; fatty alcohols containingfrom 12 to 26 carbon atoms, for instance octyldodecanol, 2-butyloctanol,2-hexyldecanol, 2-undecylpentadecanol and oleyl alcohol; partiallyhydrocarbon-based or silicone-based fluoro oils; silicone oils, forinstance linear or cyclic, volatile or non-volatilepolydimethylsiloxanes (PDMSs) that are liquid or pasty at roomtemperature, for instance cyclomethicones, dimethicones, optionallycomprising a phenyl group, for instance phenyl trimethicones,phenyltrimethylsiloxydiphenyl siloxanes,diphenylmethyldimethyltrisiloxanes, diphenyl dimethicones, phenyldimethicones and polymethylphenylsiloxanes; mixtures thereof.

These oils may be present in a content ranging from 0.01% to 90% andbetter still from 0.1% to 85% by weight, relative to the total weight ofthe composition.

The composition according to the invention may also comprise one or moreorganic solvents that are cosmetically acceptable (acceptabletolerability, toxicology and feel).

These solvents may generally be present in a content ranging from 0% to90%, preferably from 0.1% to 90% and more preferably from 10% to 90% byweight, and better still from 30% to 90%, relative to the total weightof the composition.

As solvents that may be used in the composition of the invention,mention may be made of acetic acid esters, for instance methyl acetate,ethyl acetate, butyl acetate, amyl acetate, 2-methoxyethyl acetate orisopropyl acetate; ketones, for instance methyl ethyl ketone or methylisobutyl ketone; hydrocarbons, for instance toluene, xylene, hexane orheptane; aldehydes containing from 5 to 10 carbon atoms; etherscontaining at least 3 carbon atoms; and mixtures thereof.

The waxes may be hydrocarbon-based waxes, fluoro waxes and/or siliconewaxes and may be of plant, mineral, animal and/or synthetic origin. Inparticular, the waxes have a melting point of greater than 25° C. andpreferably greater than 45° C.

As waxes that may be used in the composition of the invention, mentionmay be made of beeswax, carnauba wax or candelilla wax, paraffin,microcrystalline waxes, ceresin or ozokerite; synthetic waxes, forinstance polyethylene waxes or Fischer-Tropsch waxes, or silicone waxes,for instance alkyl dimethicones or alkoxy dimethicones containing from16 to 45 carbon atoms.

The gums are generally polydimethylsiloxanes (PDMSs) of high molecularweight or cellulose gums or polysaccharides and the pasty substances aregenerally hydrocarbon-based compounds, for instance lanolins andderivatives thereof, or PDMSs.

The nature and amount of the solid substances depend on the desiredmechanical properties and textures. As a guide, the composition maycontain from 0 to 50% by weight and better still from 1% to 30% byweight of waxes, relative to the total weight of the composition.

The polymer may be combined with one or more auxiliary film-formingagents. Such a film-forming agent may be chosen from any compound knownto those skilled in the art as being capable of fulfilling the desiredfunction, and may be chosen especially from plasticizers and coalescers.

The composition according to the invention may also comprise one or moredyestuffs chosen from water-soluble dyes and pulverulent dyestuffs, forinstance pigments, nacres and flakes that are well known to thoseskilled in the art. The dyestuffs may be present in the composition in acontent ranging from 0.01% to 50% by weight and preferably from 0.01% to30% by weight, relative to the weight of the composition.

The term “pigments” should be understood as meaning white or coloured,mineral or organic particles of any form, which are insoluble in thephysiological medium and which are intended to colour the composition.

The term “nacres” should be understood as meaning iridescent particlesof any form, produced especially in the shell of certain molluscs, oralternatively synthesized.

The pigments may be white or coloured, and mineral and/or organic. Amongthe mineral pigments that may be mentioned are titanium dioxide,optionally surface-treated, zirconium oxide or cerium oxide, and alsozinc oxide, iron oxide (black, yellow or red) or chromium oxide,manganese violet, ultramarine blue, chromium hydrate and ferric blue,and metal powders, for instance aluminium powder or copper powder.

Among the organic pigments that may be mentioned are carbon black,pigments of D & C type, and lakes based on cochineal carmine or onbarium, strontium, calcium or aluminium.

The nacreous pigments may be chosen from white nacreous pigments such astitanium-coated mica or bismuth oxychloride-coated mica, colourednacreous pigments such as titanium mica coated with iron oxides,titanium mica coated especially with ferric blue or with chromium oxide,titanium mica coated with an organic pigment of the abovementioned typeand also nacreous pigments based on bismuth oxychloride.

The water-soluble dyes are, for example, beetroot juice or methyleneblue.

The composition according to the invention may also comprise one or morefillers, especially in an amount ranging from 0.01% to 50% by weight andpreferably ranging from 0.01% to 30% by weight, relative to the totalweight of the composition. The term “fillers” should be understood asmeaning colourless or white, mineral or synthetic particles of any form,which are insoluble in the medium of the composition, irrespective ofthe temperature at which the composition is manufactured. These fillersserve especially to modify the rheology or texture of the composition.

The fillers may be mineral or organic of any form, platelet, sphericalor oblong, irrespective of the crystallographic form (for exampleleaflet, cubic, hexagonal, orthorhombic, etc.). Mention may be made oftalc, mica, silica, kaolin, polyamide powder (Nylon®) (Orgasol® fromAtochem), poly-β-alanine powder and polyethylene powder,tetrafluoroethylene polymer (Teflon®) powders, lauroyllysine, starch,boron nitride, hollow polymer microspheres such as those ofpolyvinylidene chloride/acrylonitrile, for instance Expancel® (NobelIndustrie) or of acrylic acid copolymers (Polytrap® from the company DowCorning) and silicone resin microbeads (for example Tospearls® fromToshiba), polyorganosiloxane elastomer particles, precipitated calciumcarbonate, magnesium carbonate, magnesium hydrocarbonate,hydroxyapatite, hollow silica microspheres (Silica Beads® fromMaprecos), glass or ceramic microcapsules, metal soaps derived fromorganic carboxylic acids containing from 8 to 22 carbon atoms andpreferably from 12 to 18 carbon atoms, for example zinc stearate,magnesium stearate, lithium stearate, zinc laurate or magnesiummyristate.

The composition according to the invention may also contain ingredientscommonly used in cosmetics, such as vitamins, thickeners, traceelements, softeners, sequestering agents, fragrances, acidifying orbasifying agents, preserving agents, sunscreens, surfactants,antioxidants, agents for preventing hair loss, antidandruff agents andpropellants, or mixtures thereof.

Needless to say, a person skilled in the art will take care to selectthis or these optional additional compound(s), and/or the amountthereof, such that the advantageous properties of the compositioncorresponding to the invention are not, or are not substantially,adversely affected by the envisaged addition.

The composition according to the invention may especially be in the formof a suspension, a dispersion, a solution, a gel, an emulsion,especially an oil-in-water (O/W) or water-in-oil (W/O) emulsion, or amultiple emulsion (W/O/W or polyol/O/W or O/W/O emulsion), in the formof a cream, a paste, a mousse, a dispersion of vesicles, especially ofionic or nonionic lipids, a two-phase or multi-phase lotion, a spray, apowder, a paste, especially a soft paste (especially a paste having adynamic viscosity at 25° C. of about from 0.1 to 40 Pa.s at a shear rateof 200 s⁻¹ after measurement for 10 minutes in cone/plate geometry) .The composition may be anhydrous, for example it may be an anhydrouspaste.

A person skilled in the art may select the appropriate presentationform, and also the method for preparing it, on the basis of his generalknowledge, taking into account firstly the nature of the constituentsused, especially their solubility in the support, and secondly theintended use of the composition.

The composition according to the invention may be a makeup composition,for instance complexion products (foundations), rouges, eye shadows, lipproducts, concealer products, blushers, mascaras, eyeliners, eyebrowmakeup products, lip pencils, eye pencils, nail products, such as nailvarnishes, body makeup products or hair makeup products (hair lacquer ormascara).

The composition according to the invention may also be a hair product,especially for holding the hairstyle or for shaping the hair. The haircompositions are preferably shampoos, hairsetting gels or lotions,blow-drying lotions, or fixing and styling compositions such as lacquersor sprays.

The lotions may be packaged in various forms, especially in vaporizers,in pump-dispenser bottles or in aerosol containers in order to allow thecomposition to be applied in vaporized form or in the form of a mousse.Such packaging forms are indicated, for example, when it is desired toobtain a spray or a mousse for fixing or treating the hair.

The invention will now be described with reference to the followingexamples, which are given as non-limiting illustrations.

EXAMPLES Example 1

Preparation of a Difunctional Polymerization Initiator

A difunctional initiator is prepared according to the following reactionscheme:THF/triethylamineHO—(CH₂)₄—OH+2C(CH₃)₂(Br)—C(═O)Br(CH₃)₂BrC—C(═O)—O—(CH₂)₄—O—C(═O)—C(CH₃)₂Br

To do this, 18 g (0.2 mol) of 1,4-butanediol are mixed with 100 g oftetrahydrofuran and the mixture is allowed to equilibrate for 10 minutesat room temperature. 40.4 g (0.4 mol) of triethylamine are then addedslowly, over a period of 30 minutes, so that the temperature of thesolution does not rise suddenly. 92 g (0.4 mol) of 2-bromoisobutyrylbromide are then added very slowly, over a period of 3 hours, and withcooling to 5° C. During this addition, a gradual yellowing of thereaction solution is observed. Stirring is continued overnight at 25° C.and the temperature is then allowed to rise gradually to roomtemperature.

The reaction solution is concentrated by evaporating off the THF and theresidue is precipitated in water. The aqueous phase is then extractedthree times with ethyl ether, and the ether phase is then dried overmagnesium sulphate.

After evaporating off the ether, 63 g of bis(n-butyl1,4-bromoisobutyrate) are thus obtained, which corresponds to a yield of80%.

Example 2

Preparation of a Poly(Methyl Acrylate-B-Butyl Acrylate-B-MethylAcrylate) Triblock Copolymer

Step I: Polymerization of N-Butyl Acrylate, Tg=−50° C.

1.43E-03 mol, i.e. 5.54E-01 g, of difunctional initiator prepared inExample 1, 2.86E-03 mol, i.e. 4.10E-01 g of CuBr, 7.81E-01 mol, i.e. 100g, of butyl acrylate and 2.86E-03 mol, i.e. 4.95E-01 g, ofN,N,N′,N″,N″-pentamethyldiethylenetriamine are mixed together in ahermetic reactor comprising a nitrogen inlet and protected from oxygen.

The mixture is heated, under a nitrogen atmosphere, to a temperature of90° C., the nitrogen inlet is closed and the temperature is maintainedfor 7 hours 30 minutes, resulting in the production of a solution of thepolymer.

This solution of the polymer is passed through a bed of neutral aluminaand the clear solution is then precipitated in 5 volumes of amethanol/water mixture (80/20).

Step II: Polymerization of Methyl Acrylate, Tg=+10° C.

1.31E-04 mol, i.e. 10.5 g, of the above macroinitiator: functionalpolybutyl acrylate, 2.62E-04 mol, i.e. 2.59E-02 g of CuBr, 8.40 ml ofdiphenyl diether solvent, 2.62E-04 mol, i.e. 4.53E-02 g, ofN,N,N′,N″,N″-pentamethyldiethylenetriamine and 3.93E-02 mol, i.e. 3.39g, of methyl acrylate monomer are mixed together in a hermetic reactorcomprising a nitrogen inlet and protected from oxygen.

The mixture is reacted for 4 hours at 90° C. and is then allowed to coolto room temperature. The solution is dissolved in about 100 ml ofdichloromethane. This solution of the polymer is passed through a bed ofneutral alumina and the clear solution is then precipitated in 5 volumesof a methanol/water mixture (80/20).

6 g of polymer in the form of a paste are obtained, which corresponds toa yield of 43% by weight.

The paste is washed with hot heptane to remove therefrom any residualmonomers present.

The weight-average and number-average molar mass are determined by gelpermeation liquid chromatography (THF solvent, calibration curveestablished with linear polystyrene standards).

The number-average molar mass (M_(n)) is equal to 88,000 g/mol and theweight-average molar mass (M_(w)) is equal to 102,000 g/mol.

The copolymer has two glass transition temperatures T_(g), the firstequal to −47° C. attributable to the poly(butyl acrylate) block, and thesecond equal to 10° C., attributable to the poly(methyl acrylate)blocks.

The “tack” value for this polymer, measured by the method describedabove, is 3.5 N.

Example 3

Preparation of a Lacquer

An aerosol is prepared with 100 g of a solution at 9% by weight of thecopolymer prepared in Example 2 in ethanol and 75 g of dimethyl etheracting as propellent gas.

The composition is sprayed onto locks of chestnut-coloured hair 18 cmlong, and the hold of the hairstyle and the supple appearance of thelocks are evaluated by a panel of 5 individuals, using a grading scaleranging from 0 (poor) to 5 (excellent).

The grades obtained are 4 for the hold of the hairstyle and 4 for thesupple appearance of the locks.

Example 4

Preparation of a “Basecoat” for a Nail Varnish

The copolymer is dissolved in ethyl acetate: the polymer content of thesolution obtained is 25% by weight. The copolymer solution of Example 2is applied to a nail. After drying for 10 minutes, a standardsolvent-based nail varnish is applied.

The strength of the varnish and the impact strength are improved.

1. A linear, block ethylenic copolymer, comprising: at least two blockshaving different glass transition temperatures, Tg; at least one ofthese blocks having a glass transition temperature of less than or equalto 20° C.; said copolymer also having an adhesion or tack value ofgreater than 1N wherein the block with a Tg of less than or equal to 20°C. is a homopolymerderived from (meth)acrylate monomers, which are suchthat the homopolymers prepared from these monomers have glass transitiontemperatures of less than or equal to 20° C.
 2. The copolymer accordingto claim 1, which is a film-forming copolymer.
 3. The copolymeraccording to claim 1, wherein the adhesion or tack value is greater than2N.
 4. The copolymer according to claim 3, wherein the adhesion or tackvalue is greater than 3N.
 5. The copolymer according to claim 1, whereinthe difference in glass transition temperatures, Tg between the twoblocks having different glass transition temperatures is from 40 to 120°C.
 6. The copolymer according to claim 5, wherein the difference inglass transition temperatures, Tg between the two blocks havingdifferent glass transition temperatures is from 40 to 110° C.
 7. Thecopolymer according to claim 5, in which the difference in glasstransition temperatures, Tg, between the two blocks having differentglass transition temperatures is from 40 to 100° C.
 8. The copolymeraccording to claim 1, wherein the number-average mass of the copolymeris from 10,000 to 500,000.
 9. The copolymer according to claim 1,wherein the proportion of the block with a glass transition temperatureof less than or equal to 20° C. is from 99% to 40% by mass of thecopolymer.
 10. The copolymer according to claim 9, wherein theproportion of the block with a glass transition temperature of less thanor equal to 20° C. is from 95% to 55%.
 11. The copolymer according toclaim 1, wherein the block with a Tg of less than or equal to 20° C. hasa Tg from 20° C. to −100° C.
 12. The copolymer according to claim 11,wherein the block with a Tg of less than or equal to 20° C. has a Tgfrom 20° C. to −95° C.
 13. The copolymer according to claim 1,comprising at least one hydrophilic block which comprises at least onehydrophilic monomer.
 14. The copolymer according to claim 13, whereinsaid hydrophilic block is a block with a glass transition temperature ofgreater than 20° C.
 15. The copolymer according to claim 13, saidhydrophilic block is a block with a glass transition temperature of lessthan or equal to 20° C.
 16. The copolymer according to claim 13, whereinsaid hydrophilic block comprises one or more hydrophilic monomers whosecorresponding homopolymers have glass transition temperatures of greaterthan 20° C. and one or more other non-hydrophilic monomers whosehomopolymers have Tg values of less than or equal to 20° C.
 17. Thecopolymer according to claim 13, wherein said hydrophilic blockcomprises from 70% to 100% of hydrophilic monomers wherein the Tg valuesof the corresponding homopolymers are greater than 20° C.
 18. Thecopolymer according to claim 13, wherein said hydrophilic blockcomprises from 10% to less than 70% of hydrophilic monomers wherein theTg values of the corresponding homopolymers are greater than 20° C. 19.The copolymer according to claim 13, wherein said at least onehydrophilic monomer is a member selected from the group consisting of acationic monomer, anionic monomer, and nonionic monomer.
 20. Thecopolymer according to claim 19, wherein the hydrophillic monomer isselected from the group consisting of 2-vinylpyridine; 4-vinylpyridine;dimethylaminoethyl methacrylate; diethylaminoethyl methacrylate;dimethylaminopropylacrylamide; and salts thereof.
 21. The copolymeraccording to claim 19, wherein the hydrophillic monomer is at least onemember selected from the group consisting of acrylic acid, methacrylicacid, crotonic acid, maleic anhydride, itaconic acid, fumaric acid,maleic acid, styrenesulphonic acid, acrylamidopropanesulphonic acid,vinylbenzoic acid, vinylphosphonic acid, and salts thereof.
 22. Thecopolymer according to claim 19, wherein the hydrophillic monomer is atleast one member selected from the group consisting of: hydroxyalkyl(meth)acrylate wherein the alkyl group contains from 2 to 4 carbonatoms; vinyllactam; (meth) acrylamide and N—(C₁ to C₄) alkyl(meth)-acrylamide; and polysaccharide (meth)acrylates.
 23. The copolymeraccording to claim 1, wherein the copolymer is at least one memberselected from the group consisting of a diblock copolymer, triblockcopolymer, and multiblock copolymer having more than three blocks. 24.The copolymer according to claim 23, wherein the copolymer is amultiblock copolymer, wherein one or two blocks have a Tg of less thanor equal to 20° C. and the other blocks have a Tg of greater than 20° C.and less than 20° C.
 25. The copolymer according to claim 1, wherein theone or more monomers is selected from the group consisting of anethylenic hydrocarbon of 2 to 10 C; an acrylate of formula CH₂═CHCOOR₁,wherein R₁ representing a linear or branched 1 to 12 C alkyl group withthe exception of a tert-butyl group, in which one or more hetero atomschosen from O, N and S is optionally inserted, the said alkyl group alsopossibly being optionally substituted with one or more substituentschosen from hydroxyl groups and halogen atoms, or R₁ represents a C₁-C₁₂alkyl-POE with repetition of the oxyethylene unit from 5 to 30 times,for example methoxy POE, or R₁ represents a polyoxyethylene groupcomprising from 5 to 30 ethylene oxide units; a methacrylate of formula:

wherein R₂ representing a linear or branched 3 to 12 C alkyl group, inwhich one or more hetero atoms chosen from O, N and S is(are) optionallyinserted, the said alkyl group possibly also being optionallysubstituted with one or more substituents chosen from hydroxyl groupsand halogen atoms; a vinyl ester of formula:R₃—CO—O—CH═CH₂ wherein R₃ represents a linear or branched 2 to 12 Calkyl group; a vinyl ether of a 1 to 12 C alkyl; and a N-(1 to 12C)alkyl acrylamide.
 26. A cosmetic composition comprising the copolymeraccording to claim
 1. 27. The cosmetic composition according to claim26, comprising from 0.1% to 60% by weight of the copolymer.
 28. Thecosmetic composition according to claim 26, further comprising aphysiologically acceptable medium in which the copolymer is in dissolvedor dispersed form.
 29. The cosmetic composition according to claim 28,wherein the physiologically acceptable medium comprises one or moresuitable solvents forming a hydrophilic phase, wherein the one or moresuitable solvents is selected from the group consisting of water,hydrophillic organic solvent, alcohol, linear lower monoalcohols havingfrom 2 to 5 carbon atoms, branched lower monoalcohols having from 2 to 5carbon atoms, ethanol, isopropanol, n-propanol, polyol, glycerol,diglycerol, propylene glycol, sorbitol, pentylene glycol andpolyethylene glycol.
 30. The cosmetic composition according to claim 28,wherein the hydrophilic phase further comprises hydrophilic C₂ ethers,C₂ to C₄ aldehydes, or mixtures thereof.
 31. The cosmetic compositionaccording to 30, wherein said physiologically acceptable medium furthercomprises a fatty phase comprising fatty substances that are liquid orsolid at room temperature, wherein the fatty substances are of animal,plant, mineral or synthetic origin.
 32. The cosmetic compositionaccording to claim 31, further comprising one or more cosmeticallyacceptable organic solvents.
 33. The cosmetic composition according toclaim 32, wherein said physiologically acceptable medium furthercomprises one or more auxiliary film-forming agents selected from thegroup consisting of a plasticizer and coalescer.
 34. The cosmeticcomposition according to claim 26, further comprising one or moredyestuffs selected from the group consisting of a water-soluble dye andpulverulent dyestuff, pigment, nacre, and flake.
 35. The compositionaccording to claim 26, further comprising fillers.
 36. The cosmeticcomposition according to claim 26, further comprising one or moreingredients cselected from the group consisting of a vitamin, thickener,grace element, softner, sequestering agent, fragrance, acidifying agent,basifying agent, preserving agent, sunscreen, surfactant, antioxidant,agent for preventing hair loss, antidandruff agent, propellant, andmixtures thereof.
 37. The cosmetic composition according to claim 26,which is in a form selected from the group consisting of a suspension, adispersion, a solution, a gel, an emulsion, an oil-in-water emulsion, awater-in-oil emulsion, and a multiple emulsion.
 38. The cosmeticcomposition according claim 26, which is a product selected from thegroup consisting of a hair product, a lacquer, and a shampoo.
 39. Thecosmetic composition according to claim 26, wherein the composition isselected from the group consisting of a makeup composition and a nailvarnish.
 40. A process for making up or caring for keratin materials,comprising contacting the cosmetic composition according to claim 26 tothe keratin materials.
 41. A method to improve the styling power and thehold of a hair lacquer, comprising contacting the copolymer according toclaim 1 with the hair lacquer.
 42. A method to increase the adhesion ofa nail varnish, comprising contacting the copolymer according to claim 1with the nail varnish.
 43. A method to improve the hold and adhesion ofa makeup composition, comprising contacting the copolymer according toclaim 1 with the makeup composition.